This gas block replaces your existing front sight and allows the user to mount accessories to its two picatinny rails. This gas block allows the mounting of our forearms without the removal of your muzzle accessory.  Purchase our gas block mounted flip front sight (YHM-9584) to retain your iron sights.

Specifications:

Mounted by the use of four socket head cap screws using a 7/64″ Allen wrench
Bore diameter of .750 inches
Made from high quality steel
Finished with a Mil. Spec. phosphate coating.